SKA Site Shared

After many months of deliberations, the Square Kilometre Array Organisation has announced that the massive telescope will be shared between Australia/NZ and South Africa.

“The decision is a complex one, which recognises the enormous amount of international investment that will be needed to make the SKA happen.

The array will be split between Africa and Australia/NZ. What this does not mean is that half the telescope will be built in each continent. Each site gets a full square kilometre of collecting area, with the full scientific functionality originally envisaged.

However, the SKA's science goals require a facility that can tune into radio waves from 70 MHz up to above 10,000 MHz. It's impossible for any single technology to cover this vast range, so the plan has always been to build two or even three different types of antennas, which together can span the full range needed.

What the SKA project has decided is to put different technologies in different places, playing to the strengths of each site. The lowest frequency component, consisting of antennas that do not move or steer and that can collect signals from the whole sky at once, will be built in Australia and New Zealand. This capitalises on the superb radio quietness of the SKA core planned for Murchison in outback Western Australia – one of the few places on the planet that isn't polluted by FM radio and other artificial signals in this low frequency band.

The higher frequency technology, consisting of more traditional steerable dishes like the one at Parkes, will be built in Africa. This naturally extends on the MeerKAT array of dishes already under construction at the SKA core site in the Karoo desert region of South Africa.

The remaining piece of the puzzle are "phased array feeds", the fish-eye lens technology being developed by CSIRO for their Australian SKA Pathfinder (ASKAP) in Western Australia. These will be further developed and expanded in Australia and NZ, and then possibly later installed on dishes in Africa. Aus/NZ technology on an African telescope is truly a win–win scenario.

The money committed to construction by all the SKA's international partners can now begin to flow. The hard-working engineers and scientists in Aus/NZ and in Africa can go back to collaborating rather than competing. And the SKA will attract brilliant young researchers from around the world to help solve the daunting technological challenges ahead of us.

I am excited that the SKA now looks like it's really going to happen. I can't wait to point it at my favourite stars and galaxies, and to get the data in my hands!”

Professor Bryan Gaensler is Director of the Centre for All-sky Astrophysics at Sydney University, and was formerly the International Project Scientist for the Square Kilometre Array.

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“Congratulations to our South African partners in this venture. Australia has a magnificent site at Boolardy, where the infrastructure in just about completed. We look forward to playing a key role in the development of a major low frequency telescope in Australia. This telescope will image the birth of the first stars in the universe.

Australia should not be put off by having been chosen for the low frequency part of the SKA project. There will be some real excitement around the low frequency work in the next decade, and it is where we have been putting most of our efforts.

We shouldn’t underestimate the complexity of this project. Phase 2 will be especially challenging given the current state of the world economy.”

Professor Rachel Webster is with the School of Physics at the University of Melbourne.

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“The Hubble Space Telescope has transformed our understanding of the universe. Now this giant radio telescope will take us further: testing Einstein’s theory of general relativity; looking for dark energy; probing for evidence of life; and much more.

The telescope will also be a beacon for science – especially in Africa – where it will inspire a generation of Africans to engage with science and engineering.

The decision is a sensible compromise that takes advantage of the considerable investment in infrastructure and technological development already in place in Southern Africa and Australasia.

Each site will operate with different and complementary observational capabilities. In Australia, wide-field receivers will be employed for large area surveys (including investigating the enigmatic dark matter) and low frequency phased arrays will look back to the time when stars and galaxies first started to form.”

Dr Marc Duldig is an astrophysicist and the President of the Australian Institute of Physics.

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“I welcome the SKA Organisation's announcement of a dual-site implementation for the telescope in Australasia and Southern Africa. This solution leverages the considerable investment made by both parties, whilst boosting the commitment to developing the planned high-tech components of the array.

I look forward to sharing this journey of astronomical discovery with all the international partners in this exciting global science project.”

“This project will have implications and benefits for the entire planet, and it is therefore fitting that it should be achieved through international collaboration. Building major scientific infrastructure will help attract to Australia scientists from around the world, and give Australian scientists the opportunity to extend their reach and experience beyond our shores.”

Professor Suzanne Cory is President of the Australian Academy of Science.